Fig. 1. Schematic of the sensor

Fig. 2. Interference spectra of normal Vernier effect

Fig. 3. Interference spectra of first-order harmonic Vernier effect

Fig. 4. Interference spectra of second-order harmonic Vernier effect

Fig. 5. Interference spectra of individual SI1 and SI2

Fig. 6. Parallel interference spectra of SI1 and SI2 at temperatures T₀ °C and T₀+1 °C

Fig. 7. Interference spectra of individual SI1 and SI2

Fig. 8. Parallel interference spectra of SI1 and SI2 at temperatures of 40 °C and 41 °C

Fig. 9. Peak wavelength /cross-point of the spectrum versus temperature